Best Buy Co. showed signs of starting to reverse declining sales during the critical holiday selling season, a better-than-expected result. It has been facing tough competition from discounters and online retailers. To combat this, it has instituted a cost-cutting program, invested in more employee training, and put an online price matching policy in place for November and December. The chain said revenue at stores open at least a year fell 1.4 percent for the nine weeks ended Jan. 5.